JP2868668B2 - Spectral colorimeter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spectral colorimeter.

[0002]

2. Description of the Related Art Conventionally, as shown in, for example, FIG. 3, a sample 1 is irradiated with light, and reflected light from the sample 1 is transmitted through a lens 2.
The collimated light is received by the slit 3 of the slit plate 3.
A, the light is guided to the concave grating 4 to be split, and the separated light is received by the light receiving element array 5, the spectral distribution (spectrum) of the sample 1 is measured, and the color is expressed as a numerical value. There is.

[0003]

In the conventional spectral colorimeter shown in FIG. 3, for example, as shown in FIG. 4, when measuring a sample 1A having a small area, the lens 2 is required to receive collimated light. It is necessary to place the imaging lens 6 on the front side of the sample 2 and use the reflected light from the sample 1A as collimated light.

[0004] Here, the imaging lens 6 must be so set that the sample 1A is at the focal position, so that an image of the sample 1A is formed on the slit 3A.

[0005] Therefore, the accuracy of the distance of the imaging lens 6 from the sample 1A is required, and even if the distance is slightly deviated, there arises a problem that the measurement accuracy is reduced.

[0006] The present invention has been made in view of the above-mentioned conventional problems, and even if the sample has a small area,
It is an object of the present invention to provide a spectrocolorimeter that does not require precision in the distance between the sample and the optical system, and therefore can accurately measure the distance regardless of the distance between the sample and the lens.

According to the present invention, there is provided a spectral colorimeter for receiving reflected light from a sample by a collimating light receiving lens, passing the received light through a slit at a focal position of the collimating light receiving lens, and spectrally measuring the light by a spectral means. the entrance side of the collimator light receiving lens, the parallel light from the sample <br/> with collimates light in a small beam diameter, which was the collimated light obtained by enlarging the beam diameter to a light receiving diameter of the collimating light receiving lens , Toward the collimated light receiving lens
The above object is achieved by providing a beam expander that emits light. The beam expander may be detachable on an incident side optical path of the collimating light receiving lens.

[0008]

In the present invention, a beam expander for receiving collimated light with a small beam diameter and expanding the beam diameter to the diameter of the collimated light receiving lens to provide collimated light is provided in front of the collimating light receiving lens. The measurement can be performed with high accuracy without being affected by the fluctuation of the distance to the sample.

According to the second aspect, since the beam expander is detachable, the beam expander is removed from the optical path when the measurement area of the sample is large, and is installed on the optical path when the measurement area of the sample is small. Thus, the measurement can be freely performed according to the sample area.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a spectral colorimeter 10 according to this embodiment receives reflected light from a sample 12 by a collimating light receiving lens 14, and the received light is located at a focal position of the collimating light receiving lens 14. In the case where the light is split by the concave grating 18 through the slit 16A , the sample 12
Is provided with a beam expander 20 which collimates and receives the parallel light with a small beam diameter and converts the parallel light into a collimated light whose beam diameter is enlarged to the light receiving diameter of the collimating light receiving lens 14.

This beam expander 20 is used to
It is composed of a concave lens 20A having a slightly larger diameter and a collimating lens 20B sharing a focus with the concave lens 20A.

The beam expander 20 is detachable on the incident side optical path 14A of the collimating light receiving lens 14.

That is, the concave lens 20A and the collimating lens 20B are mounted on the same lens barrel 22, and the lens barrel 22 is detachable on the incident side optical path 14A.

In the figure, reference numeral 16 denotes a slit plate provided with a slit 16A, 24 denotes a light receiving element array for receiving the spectral light from the concave grating 18, and 26 converts an electric signal generated by the light receiving element array 24 to a digital signal. An A / D converter 28 represents a central processing unit for processing this digital signal into a final measured value (spectrum).

In this embodiment, in the case of the sample 12 having a small measurement area, the beam expander 20 is arranged on the incident side optical path 14A of the collimating light receiving lens 14 to collimate and receive the reflected light from the sample 12. The beam is expanded to the light receiving diameter of the collimating light receiving lens 14 and the collimated light receiving lens 14
To receive light.

That is, since both the incident side and the outgoing side of the beam expander 20 are collimated light, the position of the beam expander 20 with respect to the sample 12 and the collimating light receiving lens 14, and furthermore, the collimating light receiving lens 14 and the slit plate 16 Even if the position of the sample 12 in the optical axis direction is disturbed, a predetermined measurement accuracy can always be obtained.

In the case of a sample 12A having a large measurement area as shown by a two-dot chain line in FIG. 1, the beam expander 20 is passed through a lens barrel 22 to enter an optical path 1 on the incident side.
What is necessary is just to remove from 4A.

Thus, the optical system of the spectral colorimeter 10 is the same as that of the conventional spectral colorimeter shown in FIG. 3, and the measurement can be performed by directly receiving the collimated light by the collimating light receiving lens 14.

In the above embodiment, the beam expander 20 is constituted by the concave lens 20A and the collimating lens 20B. However, the present invention is not limited to this. It is sufficient that the light is received and the beam is expanded to the light receiving diameter of the collimating light receiving lens 14 so as to be collimated light.

Therefore, for example, as shown in FIG. 2, the beam expander 21 may be constituted by the convex lens 21A and the collimating lens 21B.

Further, the spectral colorimeter 10 according to the above embodiment is used.
Is provided with a concave grating 18 and a light receiving element array 24. However, the present invention is not limited to this, and a spectral unit other than the concave grating may be used. May be another means as long as it can form a signal corresponding to the wavelength from the spectral light.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view including a partial block diagram showing an embodiment of a spectral colorimeter according to the present invention.

FIG. 2 is a schematic sectional view showing a second embodiment of the spectral colorimeter according to the present invention.

FIG. 3 is a schematic sectional view schematically showing a conventional spectral colorimeter.

FIG. 4 is a schematic sectional view showing an optical system when a sample having a small measurement area is measured by a conventional spectral colorimeter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Spectral colorimeter 12, 12A ... Sample 14 ... Collimated light receiving lens 14A ... Incident side optical path 16 ... Slit 18 ... Concave grating (spectral means) 20, 21 ... Beam expander 22 ... Lens barrel 24 ... Light receiving element array

Claims (2)

(57) [Claims] 1. A spectral colorimeter for receiving reflected light from a sample by a collimating light-receiving lens, passing the received light through a slit at the focal position of the collimating light-receiving lens, and measuring the light by spectral means. on the incident side of the light receiving lens, the parallel light from the sample with collimates light in a small beam diameter, which was the collimated light <br/> enlarging the beam diameter to a light receiving diameter of the collimating light receiving lens, wherein A spectral colorimeter comprising a beam expander for emitting light toward a collimating light receiving lens . 2. The spectral colorimeter according to claim 1, wherein said beam expander is detachable on an optical path on an incident side of said collimating light receiving lens.